The present invention relates to testing of cigarettes and analogous rod-shaped articles which constitute or form part of smokers' products. Typical examples of such rod-shaped articles are filter rod sections, plain cigarettes, cigars and cigarillos as well as filter cigarettes, cigars and cigarillos. More particularly, the invention relates to improvements in a method of testing rod-shaped articles (hereinafter called cigarettes for short) of the tobacco processing industry for the presence or absence of plural defects.
It is known to test rod-shaped articles of the tobacco processing industry for the presence or absence of two or more different defects. For example, it is known to weigh plain or filter cigarettes in order to ascertain whether the cigarettes are underweight or overweight. Underweight cigarettes are not acceptable to the smoker, and overweight cigarettes are not acceptable to the manufacturer because they contain excessive quantities of the most expensive commodity in cigarette making, namely, tobacco shreds. The testing can be carried out during manufacture or during processing of cigarettes. For example, the mass or weight of cigarettes can be determined by monitoring the mass of successive increments of a continuous cigarette rod prior to subdivision of such rod into discrete rod-shaped articles. Signals from the testing device or devices which serve to ascertain the weight of unit lengths of the rod or the weight of successive discrete cigarettes are compared with reference signals in order to determine whether or not the monitored unit lengths or discrete cigarettes are underweight or overweight. Defective cigarettes, or cigarettes produced from defective portions of the rod, are thereupon segregated from satisfactory cigarettes in order to prevent further processing or entry into the packing machine.
Filter cigarettes are also subjected to numerous tests. Such tests include, for example, ascertaining the condition of wrappers of the tobacco-containing portions, the condition of connections between the tobacco-containing portions and the filter plugs, the hardness or firmness of the tobacco-containing ends, the permeability of the wrappers, the resistance to axial flow of tobacco smoke into the mouth of the smoker, and many others. The wrappers of tobacco-containing portions are examined for the presence or absence of holes, frayed ends of the wrappers, air pockets, open seams and/or a combination of such defects. The same holds true for the testing of uniting bands which are used to connect the tobacco-containing portions of filter cigarettes with the respective filter plugs. Many manufacturers also employ testing devices which monitor the exterior of the articles for the presence or absence of smudges and for the condition of imprints representing the trademark(s), the brand name and/or the name of the manufacturer.
Many conventional testing devices are fully automated and are incorporated into cigarette making or processing machines so that each and every cigarette is tested for the presence or absence of the particular defect or defects. The testing devices are designed to generate defect signals which are transmitted to a suitable ejecting device serving to segregate defective cigarettes from satisfactory cigarettes and to propel, deposit or cause gravitational descent of segregated cigarettes into a collecting receptacle. If a machine embodies two or more testing devices, the defect signals which are generated by such plural devices are transmitted to a single ejector which segregates defective articles at a given location without "knowing" the exact nature of defects which have caused the segregation of such cigarettes from satisfactory cigarettes. As a rule, the ejector comprises a nozzle which receives blasts of compressed air to eject the defective cigarettes from their flutes or other receiving means and to propel the ejected articles into the aforementioned common receptacle.
The just discussed mode of plural testing and subsequent segregation of defective cigarettes exhibits numerous defects. One of the main drawbacks of such conventional procedures is that they do not take advantage of all possibilities which are offered by ejection of defective cigarettes, especially as regards the causes of defects, the condition of testing devices, the condition of the machine or machines wherein the testing devices are put to use, the possibility of rapidly ascertaining the cause or causes of defects, and the possibility of rapidly curing or eliminating the causes of defects such as improper operation of the machine and/or testing equipment.